Sakai Top or paperclip top demonstration.
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The physics behind:
http://jgtao.me/content/02-14-16/
Previously:
https://www.homemadetools.net/forum/...420#post127358
https://www.homemadetools.net/forum/...219#post161318
https://www.homemadetools.net/forum/...2811#post97204
https://www.homemadetools.net/forum/...670#post136574
https://www.homemadetools.net/forum/...363#post131240
https://www.homemadetools.net/forum/...421#post127361